Interferon mediated phosphatidylinositol uptake and processing in nuclei isolated from Burkitt lymphoma cells.

The kinetic analysis of exogenous [3H]phosphatidylinositol (PI) uptake and processing by nuclei isolated from Daudi lymphoma cells upon interferon alpha treatment has been performed. Results have disclosed that, with respect to controls, interferon induces an evident stimulation of label incorporation into nuclei. The incorporated [3H] PI has been found for phosphorylation and hydrolytic cleavage, indicating that the intranuclear transduction system activated by interferon at plasma membrane level, might involve the PI cycle as a possible route of intracellular signalling.

Relationship between nuclear ribonucleoprotein arrangement and cell proliferation in Burkitt lymphoma cells.

The presence of body-like structures in nuclei from interferon alpha-treated Daudi cells has been shown on the ultrastructural level, by the use of different staining methods. The degree of their rearrangement in the nucleoplasm seems to be dependent on the time of interferon treatment. Since this morphological evidence has been found to be preceded by a slowing down of RNA transcriptional machinery early upon the interferon administration, it is speculated that interferon generated signals might lead to RNP granule accumulation in the nucleus and a consequent arrangement into defined structures.

Inositol lipid-mediated intranuclear signalling: a comparative analysis of in vivo labelling in interferon alpha-sensitive and -resistant Daudi lymphoma cells.

Changes in inositol lipid and diacylglycerol metabolism have been analysed in Daudi lymphoma cells treated up to 24 h with human DNA recombinant interferon alpha. Results showing a different response of nuclear phosphoinositides and diacylglycerol, compared to whole cells, suggest that the intranuclear signalling system activated by interferon in Daudi cells involves nuclear inositol lipid metabolism. A well-characterized clone of Daudi cells selected for resistance to the antiproliferative action of interferon provided controls for the specificity of results.